Compressed air receivers have many uses in a compressed air system and one is to protect against pulse loads. In fact, these devices, if installed properly, can be used to enhance pulse loads like dust collector cleaning operations.
A common problem with dust collectors that use reverse pulse compressed air cleaning is the lack of enough stored air to provide a good solid pulse to clean the filter elements. These units typically have manifolds made of a length of pipe along which the feed to each pulse valve is connected. For example, a 6-ft length of 3-in. pipe used as storage volume has only about 2 gal of volume. The pulse, however, usually needs much more than this volume to work properly and provide a strong quick force.
A common retrofit is to install 30 to 60 gal of receiver capacity to enhance the volume of the installed manifold; this greatly increases the amount of stored air available to each cleaning pulse. And because each cleaning pulse becomes much more efficient, it is often possible to reduce the duration and frequency of pulses, saving expensive compressed air.
An additional important element in this configuration is the use of a needle valve to control the rate of fill of the new receiver. Without control of the flow, each cleaning pulse causes compressed air to rush at high velocity into the receiver and dust collector manifold to replace the air. This high demand can cause extra compressors to start, and/or could be negatively affecting the operation of any pressure sensitive equipment in the vicinity.
Installing a needle valve reduces the pulse flow, and if set correctly, allows only the flow of air required to completely fill the new receiver tank between pulses. This smooths out the flow of air, protecting the system from high flow pulses.
A secondary benefit of this configuration is to protect the system in the event of pulse valve failure, something that is a fairly common occurrence with diaphragm style pulse valves located outdoors, a condition in an unprotected system that can take down the facility due to low pressure. If a valve fails in the open position, a needle valve will limit the flow of air and protect the plant from trouble.
Of course this strategy does not need to be limited to dust collectors — the negative effects of almost any pulse load can be smoothed out in this way, making it easier to control system pressure.